Conventional calling line identification (CLID) and the associated display terminals are now known in the market. Known CLID services deliver the directory number, subscriber name or business name associated with the calling telephone line rather than the callers true identity. Human recognition of the caller, if known to the called party, must be relied on for verifying a caller's identity. However the value of human recognition is limited by the fact that the caller may not be known to the called party, or the called party may be a machine rather than a person. Thus known CLID services fail to provide an assured identity of the caller that can be acted on reliably.
Consequently the CLID cannot be acted on with certainty since the same CLID is delivered regardless of who actually places the call. For example, when all members of a household share the same CLID associated with a subscriber number, the displayed name and number does not identify which of several family members is making the call. If a call is placed by an individual away from their customary phone as would occur for a business traveller at a payphone, hotel room, or colleague's desk, the caller's personal identity is not delivered. In some situations the privacy of the caller may be violated since the caller's physical location may unwittingly be disclosed by CLID. These limitations of CLID inhibit its use in providing preferential or customized treatment for the caller regardless of location, and in automatic processing of the call in a call handling telephone switching or computer processing systems. In addition, the unreliability of CLID in providing actual caller identity precludes its use as a non-repudiation mechanism in situations, such as a phone order to a stock broker, where caller identification is critical.
A known approach to addressing the limitation of CLID is to have a computer telephony system answer the call and prompt the caller for an identifier which is then used to route the call or perform a database lookup. This however precludes the use of the caller's identity to provide selective treatment (e.g. forwarding) of the call prior to ringing the terminating device. This approach is also vulnerable to fraud since an identifier can easily be intercepted by a passive wiretap or, for example, guessed from the caller's name. For example, a known system now on the market uses the first three letters of the caller's name as the identifier.
U.S. patent application Ser. No. 09/20681 filed Dec. 11, 1998, to D. B. Gutzmann, entitled "Network calling party identification, authentication and routing in response thereto. This application provides an approach based on using an intrinsic property of the calling party, such as an audible utterance, which is compared with stored representations of a voice profile, using voice recognition technology. Alternatively, other biometric information such as a fingerprint or facial image may be used. Nevertheless such an approach requires an appropriate system and terminal equipment for collection of intrinsic information, storage of representations and processing of such information for authentication, which may not be possible with existing Calling Line ID base computer telephony systems.